A variety of "credit card" imprinters are now in use in which separate cards or plates having embossed characters thereon imprint a joined pile of forms called a "form set". In retail sales establishments a form set for recording information relating to a sales transaction may be imprinted with vendor information from a merchant plate and customer information from a credit card carried by the customer. These printers may also imprint other information such as the date of purchase. This type of printer may be of the portable variety which can be carried by the agent or employee of the vendor to the customer or may be located on a counter. It may be a heavier, more sophisticated charge printer for recording the amount of a business transaction as well as the date. In addition, similar printing devices are now used in banks to imprint deposit slips with the customer's name and account number.
In the past these printers have comprised a substantially flat, rectangular printing base on which the credit card, the merchant plate, and auxiliary printers for charge and date are mounted. A platen carriage, containing a single roller platen, travels over the printing base and impresses a form set with embossed characters from the merchant plate and credit card and from the date and charge printers. This type of printer device suffered from a number of disadvantages. First, it is difficult to get both merchant plate and credit card at the same height with respect to a single roller platen. Consequently, it is difficult to get the characters from both to print distinctly. Also, the printer must hold the form set in place without undue stress which might tear or damage the paper forms.
In U.S. Pat. No. 3,862,598 issued to Hawthorne, Jan. 28, 1975, a credit card printer device containing a platen carriage having dual rollers mounted side-by-side on the same axle is described. When the platen carriage travels in one direction across the imprinting case one roller platen, mounted loosely on the axle, is unable to imprint while the other roller, being rigidly fixed, is able to print. When the platen carriage travel ends and the direction of platen carriage motion is reversed, the loose, idle platen becomes the imprinting roller platen and the fixed imprinting platen becomes the idle platen. While this device partially cures the disadvantages previously described, it does not describe a credit card printing device of the counter set variety with accompanying charge printer. Furthermore, in the U.S. Pat. No. 3,862,598 both rollers are on the same axle and of the same radius making separate height adjustments due to differences in credit card or merchant plate thickness difficult or impossible. Also, the mechanism of U.S. Pat. No. 3,862,598 is somewhat complicated so that replacement of worn parts, such as roller platens, is comparatively difficult. Similar criticisms can be made of other devices of the prior art including U.S. Pat. No. 3,272,120 issued to D. W. Johnson, Sept. 13, 1966 and U.S. Pat. No. 3,340,800 issued to J. H. Gruver et al. Sept. 12, 1967.
The improved imprinting device of this invention contains a platen carriage having dual roller platens set on separate parallel roller platen axles each of whose heights is individually adjustable thus allowing a superior way of adjusting to the proper printing levels for the different printing elements, as well as permitting the use of printing surfaces requiring less accuracy than the aforementioned devices or other devices of the prior art. In addition, the positioning of the roller platens closer to the leading edge of the platen carriage facilitates a shorter base, since the device's printing sequence can be reversed earlier than on one which has the print rollers located in the center of the platen carriage.